Geology Chapter 10 part 1 – Flashcards
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The surfaces named contacts #2 and #3 are examples of ____________.
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unconformities
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Contact #1 is an example of a(n) ____________.
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fault
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The oldest geologic unit in the cross section is the ____________.
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limestone
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The youngest geologic unit visible in the cross section is the ____________.
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conglomerate
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The marble rind surrounding the granite pluton must be younger than the limestone according to the principle of ____________.
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baked contacts
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Concerning relative ages of the shale and sandstone, ____________.
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the sandstone must be older, according to the principle of superposition
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Concerning relative ages of the granite and sandstone, ____________.
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their relative ages cannot be determined from the information given
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Basaltic clasts within the basal layers of the conglomerate imply which of the following statements? (Choose the most correct answer.)
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The basalt must be the older of the two. The section must not have been overturned by tectonic activity at any time.
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Basaltic clasts within the conglomerate have been radiometrically dated to 50 million years ago (Eocene Epoch of the Tertiary Period). Is this a reliable age for the conglomerate?
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No, this age is likely too old.
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Concerning the relative ages of the basalt and the fault, ____________.
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the basalt must be older, according to the principle of cross-cutting relationships
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The basalt body is best described as a ____________.
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dike
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Contact #3 is both a ____________ at various points.
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disconformity and a nonconformity
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Which statement about contact #3 is correct?
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It and contact #2 once formed a continuous unconformity.
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James Hutton, the "father of geology," put forth the principle of ____________.
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uniformitarianism
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Period names on the geologic time scale, such as Devonian and Permian, provide examples of ____________.
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relative age
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In an undisturbed sequence of sedimentary rocks, younger layers overlay older layers, according to the principle of ____________.
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superposition
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If the lithology and fossil content of two bodies of rock on opposite sides of a canyon are identical, then these remaining outcrops were likely physically connected at one time and formed part of an extensive, sheet-like layer of rock. This idea summarizes the principle of ____________.
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original continuity
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Which of the following geologic principles is a direct result of gravity?
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original horizontality
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Which of the following geologic principles is NOT a result of gravity?
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cross-cutting relationships
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Relative ages expressed on the geologic time scale primarily resulted from the study of ____________.
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fossil content and spatial relationships among sedimentary rocks
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Numerical ages for boundaries between time units on the geologic time scale primarily resulted from the study of ____________, in conjunction with relative age data.
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radiometric dating of igneous rocks
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Within the world's sedimentary rocks, fossils ____________.
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occur in an ordered sequence
